Transportation of large quantities of substances via large truck and truck/trailer combinations has occurred for at least the past thirty years. Indeed, over these thirty years, various needs and developments have occurred in connection with this industry. For example, U.S. Pat. No. 3,272,546, issued to Cooley on Sep. 13, 1966, illustrates a truck/tractor unit which cooperates with a trailer platform in order to transport a substance-carrying container from one location to another. As another example, U.S. Pat. No. 3,152,837, issued to Margala and entitled "Dumping Semi-Trailer", discloses a double-ended semi-trailer, either end of which may be connected to a tractor for transporting substances stored in a pair of load-carrying bodies. Each of the load-carrying bodies are pivotally connected to the structure so that each may be tilted in an upward fashion to exhaust or dump the stored substance out of the respective load-carrying body.
More recently, it has been recognized that trucks constructed to transport only a single substance give rise to great inefficiencies where it is desirable to transport different substances between different destinations. For example, in mining operations, it is often desirable to carry a mining liquid from the storage site to the mine, and to carry the mined material, such as ore, from the mining site to the storage site. When using prior art trucks capable of transporting only one substance, however, inefficiencies arise because each one-substance truck is only capable of bringing a full load of a single type in one direction (i.e., either fluid from the storage site to the mine, or ore from the mine to the storage site), requiring that its return trip to its original location be made with no load whatsoever. Thus, as the empty one-substance truck returns from its delivery destination, various resources are expended, such as time, fuel, wear and tear on the vehicle and money, while no transportation of substance is being accomplished.
In addition to multiple substance transportation, another challenge which has arisen is that of balanced load distribution during transportation of a substance. In particular, various federal and state regulations apply to the trucking industry which govern the weight distribution of a load on a truck or truck trailer. These rules ensure safety and efficiency when hauling large quantities of substance.
Several prior art attempts have been made to accomplish balanced load distribution. For example, U.S. Pat. No. 4,033,625, issued Jul. 5, 1977, to Fikse, is entitled "Adjustable-Length Semitrailer Chassis and Method of Semitrailer Maneuvering" (the "Fikse Patent"). The Fikse Patent discloses a truck semi-trailer having frames adjustable in length so as to alter the overall length of the trailer. The change in length also changes the distribution of the weight of the trailer and the load which it carries. Another example is U.S. Pat. No. 4,877,293, issued Oct. 31, 1989, to French et al., and entitled "Load Bridging Dump Trailer" (the "French Patent"). The French Patent also discloses a truck trailer with an extendable frame to permit even load weight distribution. A final example is U.S. Pat. No. 4,943,118, issued Jul. 24, 1990, to Davis, and entitled "End Dumping Trailer" (the "Davis Patent"). The Davis Patent discloses a substance-carrying bed for placement on a truck trailer, the bed having wheels for longitudinal movement across the trailer. The bed can be placed toward the middle of the trailer during transportation of a substance, and then rolled to the rear end of the trailer for inclined dumping once the truck has reached its destination.
While purporting to permit load distribution, both the Fikse and French Patents require complex and undoubtedly high cost trailer structure to accomplish their respective results. In addition, the process of changing the effective length of the trailer is believed to require great attention to safety and surroundings during the extension/retraction process. While the Davis Patent does not disclose a changing trailer length, neither it nor the Fikse or French Patents disclose apparatus for accommodating the two-substance problem discussed above.
It is therefore an object of the present invention to provide a vehicle which is capable of transporting multiple substances between locations. As a result of this object, efficiencies are increased while costs are minimized.
It is a further object to provide a two-substance vehicle which permits either substance container to be situated in an appropriate location on the trailer in order to achieve appropriate payload and weight distribution to the wheel axles of the trailer.
It is still a further object of the present invention to permit tilting of at least one of the substance containers in order to exhaust the substance stored therein.
It is yet another object of the present invention to provide multiple hinge configurations on the tailgate opening of a substance container so that the tailgate may be opened in different manners to permit different types of access to the substance stored therein.
Other objects and advantages of the present invention will be apparent to those of ordinary skill in the art having reference to the following specification together with its drawings.